Supercharger

ABSTRACT

Embodiments of the invention provide a supercharger including a housing with a scroll-like upper housing at one end and a gear housing at an opposite end, and an output aperture defined by the upper housing. Some embodiments include a supercharger that has a compression chamber that is at least partially surrounded by at least a portion of the upper housing. The supercharger includes an impeller at least partially positioned in the compression chamber, and a variable or interchangeable inlet extending from the housing that defines an inlet aperture fluidly coupled to the compression chamber. Some embodiments include an anti-backlash gear assembly coupled to an impeller gear of the impeller.

BACKGROUND

Superchargers increase airflow to an engine that powers thesupercharger. The increased airflow enables the engine to burn morefuel, which results in a commensurate increase in engine power. Forexample, a centrifugal supercharger uses a small impeller driven by theengine to draw air into the supercharger from a fill side, compress theair in a compression chamber, and feed compressed air into the engine'scombustion chamber via a discharge side. On most conventionalsuperchargers, the pressure at the fill side is typically fixed, anddoes not allow for variations to optimize volumetric and thermalefficiency for specific applications. Internal lubrication of gearinginvolving transfer of power from the engine to the impeller is oftensub-optimal and can affect longevity.

SUMMARY

Some embodiments include a supercharger comprising housing including ascroll-like upper housing at one end and a gear housing at an oppositeend, and an output aperture defined by the upper housing. Someembodiments include a compression chamber at least partially surroundedby at least a portion of the upper housing, and an impeller at leastpartially positioned in the compression chamber. Some embodimentsinclude a variable or interchangeable inlet extending from the housing,where the inlet defines an inlet aperture fluidly coupled to thecompression chamber.

In some embodiments, the inlet is defined by an interchangeable inletconstrictor. In some embodiments, the inlet constrictor comprises aninner wall defining an inlet region and outlet region, and the slope ofthe inner wall is defined by an angle from a plane parallel with theopening of the outlet region. In some embodiments, the slope is about78°. In other embodiments, the slope is less than 90°.

In some embodiments of the invention, the impeller is coupled to orintegral with an impeller shaft coupled to or integral with an impellergear positioned adjacent at least one oil guide. In some embodiments,the at least one oil guide comprises a base wall coupled to or extendingfrom the gear housing towards the upper housing. In some furtherembodiments, the base wall includes one or more coupled guide wallsextending away from the gear housing, where at least one of the one ormore coupled guide walls at least partially surrounds the impeller gear.Some embodiments include an anti-backlash gear assembly coupled to agear of the impeller.

Some embodiments include a supercharger comprising a housing includingan output aperture, and a compression chamber at least partiallysurrounded by at least a portion of the housing. Some embodimentsinclude an impeller at least partially positioned in the compressionchamber that is coupled to or including an impeller shaft including animpeller gear. Some embodiments include a variable or interchangeableinlet constrictor defining an inlet aperture fluidly coupled to thecompression chamber.

In some embodiments, the inlet constrictor is coupled to or includes anedge lip defining an inlet diameter of the inlet aperture. In someembodiments, the inlet constrictor includes an outlet region comprisingan aperture with an outlet diameter, where the outlet diameter iscircumferentially defined by a coupling between a bottom surface and aninner wall of the inlet constrictor.

In some embodiments, the inner wall is sloped by an angle from a planeparallel with the opening of the outlet region. In some embodiments, theangle is about 78°. In some further embodiments, the angle is less than90°.

Some embodiments include a supercharger assembly comprising a housingincluding an output aperture, and a compression chamber at leastpartially surrounded by at least a portion of the housing. Someembodiments include an impeller at least partially positioned in thecompression chamber that is coupled to or including an impeller shaftincluding a coupled or integrated impeller gear. Some embodimentsinclude an anti-backlash gear assembly coupled to the impeller gear ofthe impeller.

Some embodiments include an inlet aperture defined by an interchangeableinlet constrictor coupled to an inlet wall of the inlet aperture, wherethe inlet constrictor comprises an inner diameter defining an inletregion at one end and an outlet diameter at an opposite end. In someembodiments, the inlet constrictor is configured to be swapped withanother inlet constrictor comprising a different inner diameter.Further, some embodiments of the assembly include at least one oil guideproximate the impeller gear.

In some embodiments, the at least one oil guide comprises a curved wallcoupled to at least a portion of the housing and at least partiallysurrounding the impeller gear. In some embodiments, the at least one oilguide comprises one or more coupled guide walls at least partiallysurrounding the impeller gear. In some further embodiments, the inletconstrictor comprises a threaded outer surface comprising a threadcomplementary to a thread of the inlet wall. In some embodiments, theinner diameter is smaller than the outlet diameter.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a front perspective view of a supercharger inaccordance with some embodiments of the invention.

FIG. 2 illustrates an exploded assembly top view of the supercharger ofFIG. 1 in accordance with some embodiments of the invention.

FIG. 3 illustrates an exploded assembly bottom view of the superchargerof FIG. 1 in accordance with some embodiments of the invention.

FIG. 4 illustrates an input gear and anti-backlash gear assembly bottomview in accordance with some embodiments of the invention.

FIG. 5 illustrates an input gear and anti-backlash gear assembly topview in accordance with some embodiments of the invention.

FIG. 6 illustrates a top perspective view of an input gear in accordancewith some embodiments of the invention.

FIG. 7 illustrates a cross-sectional view through cut-line 7 of theinput gear of FIG. 6 in accordance with some embodiments of theinvention.

FIG. 8 illustrates a cross-sectional view through cut-line 8 of theinput gear of FIG. 6 in accordance with some embodiments of theinvention.

FIG. 9 illustrates a partial cut-away perspective view of thesupercharger of FIG. 1 with inlet area reducer (inlet ring) shown inassembly view in accordance with some embodiments of the invention.

FIG. 10 illustrates a top view of the supercharger of FIG. 1 inaccordance with some embodiments of the invention.

FIG. 11 illustrates a front cross-sectional view of the supercharger ofFIG. 1 in accordance with some embodiments of the invention.

FIG. 12 illustrates a side cross-sectional view of the supercharger ofFIG. 1 in accordance with some embodiments of the invention.

FIG. 13 illustrates a cross-sectional view through cut-line 13 of FIG.12 in accordance with some embodiments of the invention.

FIG. 14 illustrates a cross-sectional view through cut-line 14 of FIG.13 in accordance with some embodiments of the invention.

FIG. 15 illustrates a side cross-sectional view of an inlet area of thesupercharger of FIG. 1 in accordance with some embodiments of theinvention.

FIGS. 16-20 illustrate side cross-sectional views of inlet area reducersin accordance with some embodiments of the invention.

FIG. 21 illustrates a top perspective view of a gear housing withassembled input gear and impeller gear with oil guides in accordancewith some embodiments of the invention.

FIG. 22 illustrates a top front perspective view of a gear housing withassembled input gear and impeller gear with oil guides in accordancewith some embodiments of the invention.

FIG. 23 illustrates a top view of a gear housing with assembled inputgear and impeller gear with oil guides in accordance with someembodiments of the invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless specified or limited otherwise, theterms “mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass both direct and indirectmountings, connections, supports, and couplings. Further, “connected”and “coupled” are not restricted to physical or mechanical connectionsor couplings.

The following discussion is presented to enable a person skilled in theart to make and use embodiments of the invention. Various modificationsto the illustrated embodiments will be readily apparent to those skilledin the art, and the generic principles herein can be applied to otherembodiments and applications without departing from embodiments of theinvention. Thus, embodiments of the invention are not intended to belimited to embodiments shown, but are to be accorded the widest scopeconsistent with the principles and features disclosed herein. Thefollowing detailed description is to be read with reference to thefigures, in which like elements in different figures have like referencenumerals. The figures, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope ofembodiments of the invention. Skilled artisans will recognize theexamples provided herein have many useful alternatives that fall withinthe scope of embodiments of the invention.

FIG. 1 illustrates a front perspective view of a supercharger 10 inaccordance with some embodiments of the invention. In some embodiments,the supercharger 10 can comprise a housing 25 including a upper housing27 at one end and a gear housing 75 at an opposite end. Further, lowerhousing 29 can be positioned coupled to and between the upper housing 27and the gear housing 75. The housing 25 can include a variety ofassemblies and components to enable the supercharger 10 to providecompressed gas or fluid (e.g., such as compressed air). In someembodiments, any ambient air flowing into the housing 25 can becompressed within the housing 25 and fed or flowed out of the housing 25as compressed air. In some embodiments, the any ambient air flowing intothe housing 25 can be compressed within the housing 25 and fed into anengine to aid in increasing the power output of the engine. In someembodiments of the invention, the supercharger 10 can include an inlet50 through which ambient air can flow into a compression chamber 55 inthe housing 25.

In some embodiments, the supercharger 10 can include an impeller 110mounted, coupled, or integrated with an impeller shaft 350. The impeller110 and associated drive components can be seen in more detail in theexploded assembly views of FIGS. 2 and 3. For example, FIG. 2illustrates an exploded assembly top view of the supercharger of FIG. 1in accordance with some embodiments of the invention. FIG. 3 illustratesan exploded assembly bottom view of the supercharger of FIG. 1 inaccordance with some embodiments of the invention. In some embodiments,the inlet 50 can be defined by one or more inlets rings 60. In someembodiments of the invention, the diameter of the inlet 50 can be variedusing one or more inlet rings 60 of different diameters. For example, insome embodiments, the inlet 50 can include a variable inlet surface 85that can be used to reduce, restrict or throttle air flow into the inlet50. Further details of the various embodiments of inlet rings 60 areshown and described below in relation to FIGS. 16-20.

In some embodiments of the invention, the impeller 110 can be mountedand/or supported in the housing 25 by lower housing 29 (shown from abottom side in FIG. 3, but shown removed from the exploded assembly viewof FIG. 2 for clarity purposes). For example, in some embodiments, theimpeller 110 can be mounted into the upper end 29 a of the lower housing29. Further, in some embodiments, the impeller 110 can be coupled, orintegrated with an impeller shaft 350 which can extend from the lowerend 29 b and through the upper end 29 a of the lower housing 29.

In some embodiments, the impeller shaft 350 can be configured to bedriven by a drive gear assembly to enable powered rotation of theimpeller 110. In some embodiments of the invention, the impeller shaft350 can comprise a central shaft 300 with a coupled or integratedimpeller gear 325. In some embodiments of the invention, the coupled orintegrated impeller gear 325 can be position in the housing 25 coupledto one or more gears of an input gear assembly 200.

In some embodiments of the invention, the impeller shaft 350 and inputgear assembly 200 can be positioned into the lower end 29 b of the lowerhousing 29. Various components can be included to enable the impellershaft 350 and input gear assembly 200 to be assembled into the lowerhousing 29. Some components include components for coupling onecomponent to another component such as a fasteners or clips, and othercomponents include components for providing seals. Still further, someother components can facilitate movement of shafts and/or gears such asbearings or bearing assemblies. For example, some embodiments includegasket 400 positioned and shaped to form a gasket seal between the lowerend 29 b of the lower housing 29 and top surface 77 of the gear housing75. Some further embodiments include a bearing assembly 425 configuredto couple to the drive shaft 230. Further, some embodiments includegasket 430 positioned for coupling to the bearing assembly 440. In someembodiments, a fastener 435 can be positioned coupled into the lowerhousing. Further, some embodiments include a clip 437 positioned betweenthe bearing assembly 425 and input gear 250, and/or clip 450 positionedadjacent the bearing assembly 490, and/or gasket 480 positioned adjacentthe bearing assembly 470.

Some embodiments include assemblies to reduce back-lash and gear noiseassociated with changes in torque. Gear backlash can occur due to a gapbetween meshing gear contact surfaces (due to design tolerance andassembly and long-term wear of gear surfaces). For example, someembodiments include a second adjacent, minor, or sub-gear that can beforced toward the rotational direction of the drive gear. The main orprimary gear can be secured to the drive shaft, while the sub-gear canbe mounted adjacent to the main gear (e.g., such as on a bushing). Insome embodiments, the force can be applied using an assembly of springsthat interconnects the two gears that can apply a spring-bias so thatthe teeth of the two gears can be out of alignment with respect to eachother. In some anti-backlash gear assemblies, the combinedout-of-alignment space of two misaligned teeth of each gear can besubstantially the same as the space between two adjacent teeth on thegear with which the anti-backlash gears are meshed (e.g., such asimpeller gear 325). For example, the input gear assembly 200 is shownfurther in FIGS. 4-7, where FIG. 4 illustrates an input gear 250 and acoupled anti-backlash gear 275 assembly bottom view in accordance withsome embodiments of the invention, and FIG. 5 illustrates an input gear250 and anti-backlash gear 275 assembly top view in accordance with someembodiments of the invention. FIG. 7 illustrates a cross-sectional viewthrough cut-line 7 of the input gear of FIG. 6 in accordance with someembodiments of the invention, and FIG. 6 illustrates a top perspectiveview of an input gear in accordance with some embodiments of theinvention. Further, FIG. 8 illustrates a cross-sectional view throughcut-line 8 of the input gear of FIG. 6 in accordance with someembodiments of the invention. In some embodiments of the invention, theinput gear assembly 200 can include anti-backlash gear 275 positionedcoupled to the input gear 250. The assembly 200 can be assembled bypassing the terminal end 225 of the drive shaft 230 through shaftaperture 290 of the gear 275. Some embodiments include an input gearassembly 200 comprising a drive shaft 230 coupled to or integrated withinput gear 250 comprising teeth 255, and an anti-backlash gear 275comprising teeth 280. For some example, in some embodiments, the inputgear 250 can include the three evenly circumferentially-spaced recesses260 for positioning of biasing springs. In one non-limiting example,springs 262 can be positioned in the recesses 260 and coupled to pins287 that are mounted into apertures 285. This assembly can enablemovement of the anti-backlash gear 275 relative to the input gear 250.For example, as the anti-backlash gear 275 rotates relative to the inputgear 250, the pins 287 can compress the springs 262 when theanti-backlash gear 275 rotates relative to the input gear 250 in onedirection. Further, as the anti-backlash gear 275 rotates relative tothe input gear 250 in an opposite direction, the pins 287 can releasethe compressed springs 262 when the anti-backlash gear 275 rotatesrelative to the input gear 250 in the other direction. As a results, insome embodiments, the movement of the anti-backlash gear 275 relative tothe input gear 250 can enable the meshing of the teeth 255 and/or theteeth 280 with the integrated impeller gear 325 with minimal noise,chatter, misalignment, etc.

FIG. 7 illustrates a cross-sectional view through cut-line 7 of theinput gear of FIG. 6 and shows springs 262 positioned in the recesses260 and coupled to pins 287. The non-limiting embodiment of FIG. 7 showsthe springs 262 are arranged substantially evenly circumferentiallyspaced in the anti-backlash gear 275. The embodiment shows three springs262, however it will be readily understood that the anti-backlash gear275 can include less than three springs 262 or more than three springs262. The positional relationship of the springs 262 and pins 287 can beseen in FIG. 8 illustrating a cross-sectional view through cut-line 8 ofthe input gear of FIG. 6 in accordance with some embodiments of theinvention.

FIG. 10 illustrates a top view of the supercharger of FIG. 1 inaccordance with some embodiments of the invention. During operation, theimpeller 110 can rotate, drawing air into the housing 25 through theinlet 50. At least some of the air can be compressed by the impeller andforced through the housing 25 towards an outlet aperture 45 defined bythe housing 25. As shown, some embodiments include a housing 25 thatcomprises a scroll-like shape. In some embodiments the housing 25 canform part of a centrifugal or centrifugal-type supercharger. In otherembodiments, the housing 25 can form part of a screw-type supercharger.In some embodiments, the internal cross-sectional diameter of thehousing 25 can progressively increase in size from a region adjacent theimpeller 110 within the housing and extending around the housing towardsthe outlet aperture 45. FIG. 11 illustrates a front cross-sectional viewof the supercharger 10 of FIG. 1 in accordance with some embodiments ofthe invention where the internal cross-sectional diameter of the housing25 is shown to be smaller on the left side of the image versus the rightside, where the region of largest cross-sectional diameter defines theoutlet aperture 45.

FIG. 12 illustrates a side cross-sectional view of the supercharger ofFIG. 1 in accordance with some embodiments of the invention, and FIG. 13illustrates a cross-sectional view through cut-line 13 of FIG. 12, andshows central shaft 300 of impeller shaft 350 of input gear assembly 200coupled to bearing assembly 470, and drive shaft 230 coupled to bearingassembly 490. FIG. 14 illustrates a cross-sectional view throughcut-line 14 of FIG. 13 in accordance with some embodiments of theinvention, and shows the position of the input gear 250 andanti-backlash gear 275 positioned with respect to impeller gear 325. Insome embodiments, the input gear assembly 200 can be powered to enablethe impeller shaft 350 and impeller 110 to rotate. For example, driveshaft 230 coupled to or integrated with the teeth 255 of the input gear250 can couple with teeth 280 of the anti-backlash gear 275 to drivetransfer power from the drive shaft to the input gear 250 andanti-backlash gear 275.

FIG. 15 illustrates a side cross-sectional view of an inlet area of thesupercharger 10 of FIG. 1 in accordance with some embodiments of theinvention. As described earlier, in some embodiments of the invention,the supercharger 10 can include an inlet 50 through which air can flowinto compression chamber 55 where the inlet 50 can be defined by one ormore inlets rings 60. In some embodiments, inlet constrictor 60 cancomprise a main body 58 that can include an inner wall 63 extending froma bottom surface 70 to an edge lip 73 that extends circumferentiallyaround the inlet constrictor 60 and defines an inlet diameter of themain body 58, and the outlet region 69 comprises an aperture with anoutlet diameter that is circumferentially defined by the couplingbetween the bottom surface 70 and the inner wall 63 (i.e., the innerwall 63 defines circular aperture at a point where the inner wall 63 andbottom surface 70 meet). In some embodiments, the edge lip 73 extendsfrom the top surface 71 to the inner wall 63. In some embodiments, theedge lip 73 is coupled to and extends between the top surface 71 and theinner wall 63. In some embodiments, the inner wall 63 includes the edgelip 73. In some embodiments, the inlet diameter of the main body 58(defined by the edge lip 73) is smaller than the outlet diameter asdescribed above. In other embodiments, the inlet diameter (defined bythe edge lip 73) is about equal to the outlet diameter. In someembodiments, the inlet constrictor 60 can include an outlet flange 62extending outwardly from the main body 58, circumferentially around theinlet region 61. In some embodiments, the inlet constrictor 60 can be aring or ring-like structure. In some other embodiments, the inletconstrictor 60 can comprise an oval or oval-shaped structure. In somefurther embodiments, the inlet constrictor 60 can comprise a square orrectangular structure.

FIG. 9 illustrates a partial cut-away perspective view of thesupercharger 10 of FIG. 1 with the inlet constrictor 60 shown inassembly view in accordance with some embodiments of the invention. Inthe non-limiting embodiment shown in FIG. 15, the edge lip 73 comprisesa curved or convex surface. In some other embodiments, the edge lip 73can have a smaller radius of curvature than shown, and in otherembodiments, the edge lip 73 can have a larger radius of curvature thanshown. Further, in some embodiments, the inlet constrictor 60 caninclude an inner wall 63 defining an inlet region 61 and outlet region69. In some embodiments, the inlet constrictor 60 can include anconstrictor thread 64 extending around an outer circumference of themain body 58. In some embodiments, the constrictor thread 64 can couplewith a complementary inlet wall thread 68 extending circumferentiallyaround the inlet wall 66 and assembled into the supercharger 10.

In some embodiments, the slope of the inner wall 63 can be defined by anangle A0 from a plane P0 parallel with the opening of the outlet region69 (i.e. the plane P0 parallel with the bottom surface 70). For example,in some embodiments, the angle A0 between the inner wall 63 and theplane P0 can be about 78°. FIGS. 16-20 illustrate side cross-sectionalviews of inlet area reducers in accordance with some embodiments of theinvention. For example, FIG. 16 illustrates a side cross-sectional viewof inlet area reducer 560 in accordance with some embodiments of theinvention. In some embodiments, the inlet constrictor 560 includes innerwall 563 defining an inlet region 561 and outlet region 569. In someembodiments, the slope of the inner wall 563 can be defined by an anglefrom a plane parallel with the opening of the outlet region 569. Forexample, in some embodiments, the angle A1 between the inner wall 563and the plane P1 can be about 90°. In some other embodiments, the slopeof the inner wall can be defined by an angle from a plane parallel withthe opening of the outlet region that is less than 90°. For example,FIG. 17 illustrates a side cross-sectional view of inlet area reducer570 in accordance with some embodiments of the invention. Someembodiments include inlet constrictor 570 with an inner wall 573defining an inlet region 571 and outlet region 579. In some embodiments,the slope of the inner wall 573 can be defined by an angle from a planeparallel with the opening of the outlet region 579. For example, in someembodiments, the angle A2 between the inner wall 573 and the plane P2can be about 88°. Further, for example, FIG. 18 illustrates a sidecross-sectional view of inlet area reducer 580 in accordance with someembodiments of the invention. In some embodiments, the inlet constrictor580 includes an inner wall 583 defining an inlet region 581 and outletregion 589. In some embodiments, the slope of the inner wall 583 can bedefined by an angle from a plane parallel with the opening of the outletregion 589. For example, in some embodiments, the angle A3 between theinner wall 583 and the plane P3 can be between about 86°. Further, forexample, FIG. 19 illustrates a side cross-sectional view of inlet areareducer 590 in accordance with some embodiments of the invention. Insome embodiments, the inlet constrictor 590 defines an inlet region 591and outlet region 599 by the inner wall 593. In some embodiments, theslope of the inner wall 593 can be defined by an angle from a planeparallel with the opening of the outlet region 599. For example, in someembodiments, the angle A4 between the inner wall 593 and the plane P4can be between about 84° Further, for example, FIG. 20 illustrates aside cross-sectional view of inlet area reducer 600 in accordance withsome embodiments of the invention. In some embodiments, the inletreducer 600 defines an inlet region 601 and outlet region 609 by theinner wall 603. In some embodiments, the slope of the inner wall 603 canbe defined by an angle from a plane parallel with the opening of theoutlet region 609. For example, in some embodiments, the angle A5between the inner wall 603 and the plane P5 can be between about 82°.One of ordinary skill in the art will recognize that the slope of theinner wall can be defined by an angle from a plane parallel with theopening of the outlet region that is less than 82°. For example, theslope of the inner wall can be defined by an angle from a plane parallelwith the opening of the outlet region that is between about 78° and 82°,between about 75° and 78°, and so on. For example, in some embodiments,the slope of the inner wall can be defined by an angle from a planeparallel with the opening of the outlet region that is less than 75°.One of ordinary skill in the art will recognize that in any of theembodiments described above, any one or more of angles A0 to A5 can varyfrom the values defined based on conventional manufacturing tolerances.For example, in some embodiments, any one or more of angles A0 to A5 canvary by 0.01 degree to 0.1 degree or between 0.01 degree and 0.5 degreebased on manufacturing tolerances. In other embodiments, any of theembodiments described above with respect to angles A0 to A5 can varyfrom the values defined based on specifications of the supercharger. Forexample, in some embodiments, any one or more of angles A0 to A5 canvary by between 0.1 and 0.5 degree or between 0.5 and 1 degree or more.

Some embodiments of the invention include one or more structures toguide flow of oil or other lubricant within the housing 25 of thesupercharger 10. For example, FIG. 21 illustrates a top perspective viewof a gear housing 75 with assembled input gear 250 and impeller gear 325with oil guide 360 in accordance with some embodiments of the invention.Further, FIG. 22 illustrates a top front perspective view of the gearhousing 75 with assembled input gear 250 and impeller gear 325 with oilguide 360 in accordance with some embodiments of the invention, and FIG.23 illustrates a top view of a gear housing 75 with assembled input gear250 and impeller gear 325 with oil guide 360 in accordance with someembodiments of the invention. As illustrated in FIGS. 21-23, in someembodiments, the oil guide 360 can be coupled to or can extend from thegear housing 75 towards the upper housing 27. In some embodiments of theinvention, the oil guide 360 can comprise a base wall 370 extending atleast partially around the impeller gear 325.

In some embodiments, the base wall 370 can comprise a curved wall asshown. In some embodiments, some portions of the base wall 370 canextend away from the gear housing 75 and towards the lower housing 29and upper housing 27. For example, in some embodiments, the base wall370 can include one or more coupled guide walls extending away from thegear housing 75. In some embodiments, the base wall 370 can include acoupled first guide wall 375 and/or a second guide wall 380. In someembodiments, the first guide wall 375 and/or the second guide wall 380can extend circumferentially at least partially around the impeller gear325. In some embodiments, the first guide wall 375 and/or the secondguide wall 380 can extend at least a partial axial length of theimpeller shaft 350. Further, in some embodiments, the first guide wall375 and/or the second guide wall 380 can extend at least a partial axiallength of the impeller gear 325. In the non-limiting example of FIGS.21-23, the first guide wall 375 and/or the second guide wall 380 cancomprise an axial length about equal to the axial length of the impellergear 325. In some other embodiments, the first guide wall 375 and/or thesecond guide wall 380 can comprise an axial length less than the axiallength of the impeller gear 325. In some further embodiments, the firstguide wall 375 and/or the second guide wall 380 can comprise an axiallength more than the axial length of the impeller gear 325.

Any of the embodiments described herein can form part of a centrifugalor centrifugal-type supercharger. In other embodiments, any of theembodiments described herein can form part of a screw-type superchargeror a roots-type supercharger. Moreover, any of the embodiments describedherein can form part of a positive displacement fluid pump.

It will be appreciated by those skilled in the art that while theinvention has been described above in connection with particularembodiments and examples, the invention is not necessarily so limited,and that numerous other embodiments, examples, uses, modifications anddepartures from the embodiments, examples and uses are intended to beencompassed by the claims attached hereto. The entire disclosure of eachpatent and publication cited herein is incorporated by reference, as ifeach such patent or publication were individually incorporated byreference herein. Various features and advantages of the invention areset forth in the following claims.

The invention claimed is:
 1. A supercharger comprising; a housing including a scroll-shape upper housing at one end and a gear housing at an opposite end; an output aperture defined by the upper housing; a compression chamber at least partially surrounded by at least a portion of the upper housing; an impeller at least partially positioned in the compression chamber, the impeller coupled to or integral with an impeller shaft; and an interchangeable inlet extending from the housing, the inlet defining an inlet aperture fluidly coupled to the compression chamber; and an anti-backlash gear coupled to an input gear for coaxial rotation therewith, whereby portions of both the anti-backlash gear and the input gear are configured and arranged to simultaneously engage an impeller gear coupled to or integral with the impeller shaft to reduce backlash.
 2. The supercharger of claim 1, wherein the inlet is defined by an interchangeable inlet constrictor and the input gear and the anti-backlash gear coupling includes springs positioned in recesses.
 3. The supercharger of claim 2, wherein inlet constrictor comprises an inner wall defining an inlet region and outlet region, the slope of the inner wall defined by an angle from a plane parallel with the face of the outlet region.
 4. The supercharger of claim 3, wherein the slope is 78°.
 5. The supercharger of claim 3, wherein the slope is less than 90°.
 6. The supercharger of claim 1, wherein the impeller shaft is coupled to or integral with an impeller gear positioned adjacent at least one oil guide, wherein at least a portion of the at least one oil guide extends at least partially around the impeller gear.
 7. The supercharger of claim 6, wherein the at least one oil guide comprises a curved base wall coupled to or extending from the gear housing towards the upper housing, and extending at least partially around the impeller gear.
 8. The supercharger of claim 7, where the base wall includes one or more coupled guide walls extending away from the gear housing, wherein at least one of the one or more coupled guide walls at least partially surrounds the impeller gear and comprises an axial length about equal to the axial length of the impeller gear.
 9. The supercharger assembly of claim 1, wherein the anti-backlash gear and the input gear portions engaging the impeller gear comprise substantially the entirety of the engagement surfaces of the anti-backlash gear and the input gear gear.
 10. A supercharger comprising; a housing including an output aperture; a compression chamber at least partially surrounded by at least a portion of the housing; an impeller at least partially positioned in the compression chamber, the impeller coupled to or comprising an impeller shaft including an impeller gear; an anti-backlash gear coupled for coaxial rotation with an input gear, the input gear including springs positioned in recesses; and an interchangeable inlet constrictor defining an inlet aperture, the inlet aperture fluidly coupled to the compression chamber.
 11. The supercharger of claim 10, wherein inlet constrictor is coupled to or includes an edge lip defining an inlet diameter of the inlet aperture.
 12. The supercharger of claim 10, wherein the inlet constrictor includes an outlet region comprising an aperture with an outlet diameter, the outlet diameter being circumferentially defined by an interface between a bottom surface and an inner wall of the inlet constrictor.
 13. The supercharger of claim 12, wherein the inner wall is sloped by an angle from a plane parallel with the face of the outlet region.
 14. The supercharger of claim 13, wherein the angle is 78°.
 15. The supercharger of claim 13, wherein the angle is less than 90°.
 16. A supercharger assembly comprising; a housing including an output aperture; a compression chamber at least partially surrounded by at least a portion of the housing; an impeller at least partially positioned in the compression chamber, the impeller coupled to or including an impeller shaft including a coupled or integrated impeller gear; an inlet aperture defined by an interchangeable inlet constrictor coupled to an inlet wall of the inlet aperture, the inlet constrictor comprising an inner diameter defining an inlet region at one end and an outlet diameter at an opposite end, wherein the inlet constrictor is configured to be swapped with another inlet constrictor comprising a different inner diameter; an anti-backlash gear coupled with an input gear, the input gear including springs positioned in recesses; and at least one oil guide proximate the impeller gear.
 17. The supercharger assembly of claim 16, wherein the at least one oil guide comprises a curved wall coupled to at least a portion of the housing and at least partially surrounding the impeller gear and extended at least a partial axial length of the impeller gear.
 18. The supercharger assembly of claim 16, wherein the at least one oil guide comprises one or more coupled guide walls at least partially surrounding the impeller gear and extending at least a partial axial length of the impeller shaft.
 19. The supercharger assembly of claim 16, wherein the inlet constrictor comprises a threaded outer surface comprising a thread complementary to a thread of the inlet wall.
 20. The supercharger assembly of claim 16, wherein the inner diameter is smaller than the outlet diameter. 